One of Hollywood's most enduring relationships has ended – Susan Sarandon and Tim Robbins have broken up after more than two decades together, PEOPLE has learned exclusively.

"Actress Susan Sarandon and her partner of 23 years, actor Tim Robbins have announced that they separated over the summer," her rep Teal Cannaday tells PEOPLE in a statement. "No further comments will be made."

The couple met on the set of Bill Durham, and they have two sons together, Jack, 20, and Miles, 17.

Sarandon, 63, was previously married to Chris Sarandon, whom she met in college. The actress also dated director Franco Amurri in the mid '80s. The two had a daughter, Eva Amurri, in 1985. (Amurri is also an actress; she most recently appeared in Showtime's Californication).

Sarandon and Robbins, 51, were admired for their long relationship in the face of the pressures of show business, their much-discussed age difference – he's 12 years younger – and that they never married.

"I won’t marry because I am too afraid of taking him for granted or him taking me for granted – maybe it will be a good excuse for a party when I am 80," Sarandon has said in the past.

I find this really sad. Any couple breaking up after twenty years is incredibly sad. These two were one of my favourite Hollywood couples. And now, here comes all the infidelity rumours. The tabloids love a high profile break up.

i just read that and i too am taken aback. if ever there was a couple that defied hollywood stereotypes,it was them. it's funny too they were together for so long...much longer than most of the short marriages last in hollywood....and they weren't even married.